1. Technical Field of the Invention
This invention relates to propoxylated modified Mannich condensates useful in the facile manufacture of rigid polyurethane foam. This invention also relates to the manufacture of rigid polyurethane foams using the propoxylated modified Mannich condensates. The invention is based upon the discovery that unique polyols are provided by propoxylating a product prepared by reacting melamine with a lower alkylene carbonate in the presence of Mannich condensates of a phenol, formaldehyde and diethanolamine. One of the unique features of the present invention is the discovery that improved reaction profiles are obtained in making rigid polyurethane foam when using the polyols of the present invention.
2. Prior Art
Wismer et al. U.S. Pat. No. 3,328,321 is directed to polyurethanes prepared from polyisocyanates and a polyhydroxy resinous reaction product of an amino-s-triazine with an alkylene carbonate or an alkylene oxide. Among the amino-s-triazines that are suggested is melamine. In the working examples Wismer et al. disclose a polyol prepared by reacting benzoguanamine with ethylene carbonate and the reaction of this polyol with an isocyanate to prepare a polyurethane foam.
Edwards et al. U.S. Pat. No. 3,297,597 is directed to Mannich condensates of a phenolic compound, formaldehyde, and an alkanolamine which are then alkoxylated, preferably with propylene oxide, to provide polyols useful in the manufacture of rigid polyurethane foams.
Edwards et al. U.S. Pat. No. 4,137,265 is similarly directed to Mannich condensates prepared by reacting a phenolic compound with formaldehyde and diethanolamine which are then propoxylated and used in the manufacture of rigid polyurethane foam.
Rudner et al. U.S. Pat. No. 4,139,501 is directed to the manufacture of flexible polyurethane foam wherein the fire retardancy properties of the foam are improved by utilizing, in its preparation, a derivative of melamine wherein one or more of the hydrogens have been replaced by a hydroxymethyl group.
Mao et al. U.S. Pat. No. 4,147,678 proposes to improve the fire retardancy properties of polyurethane elastomers by utilizing a hexaalkoxymethylol melamine as a polyol component.
Owen U.S. Pat. No. 4,198,490 is directed to the manufacture of rigid polyurethane foam from a polyol reaction product containing a N-.alpha.-alkylol, such as trimethylolmelamine.
Yukuta et al. U.S. Pat. No. 4,221,875 is directed to rigid polyurethane foams having flame resistance which are prepared from a mixture comprising a polyhydroxy compound such as an ethylene oxide adduct of a material containing a plurality of hydroxyl groups (i.e., sucrose or sorbitol), an organic polyisocyanate, a blowing agent and powdered melamine. From 20 to 60 parts by weight of powdered melamine per 100 parts of polyhydroxy compound are recommended.
Nissen et al. U.S. Pat. No. 4,293,657 discloses the preparation of a stable dispersion useful in the preparation of polyurethane foam prepared by the in situ reduction of finely powdered melamine with a stabilizer such as silicic acid, salts of perfluorinated alkylcarboxylic acids or salts of fatty alcohol sulfates.
Jacobs et al. U.S. Pat. No. 4,312,988 is directed to the preparation of hydroxy terminated melamine derivatives wherein melamine is reacted with isopropanolamine in order to minimize the amount of isomelamine impurities that are normally formed when melamine is reacted with an alkanolamine.
Pcolinsky, Jr. U.S. Pat. No. 4,317,889 and the numerous U.S. patents cited therein disclose the use of melamine derivatives such as hydroxymethyl melamines, melamine phosphate, hexaalkoxymethylmelamine, etc. as a component for use in the manufacture of flexible polyurethane foams.
Johnson U.S. Pat. No. 4,369,258 is directed to polyurethane foams prepared by reacting a polyisocyanate with a mixture of a melamine polyol with a polyol derived from a polyester or a polyether polyol.